This application claims the benefit of priority under 35 U.S.C. §119 of EP Application 04015573.1, filed Jul. 2, 2004, the contents of which are hereby incorporated by reference.
1. Field of the Invention
Subject of the present invention is a diagnostic device for determining analytes, a method for determining analytes using said device, a method for the assembling said device and an instrument for determining the presence of analytes using said devices.
2. Description of the Related Art
The invention is useful in the field of analytics, wherever a device containing immobilized reagents bound to an inner surface of said device are to be contacted with a sample to bind a component of said sample to said device. Particularly, the invention is useful in the field of diagnostics, particularly molecular diagnostics, e.g. the analysis of nucleic acid or protein components in samples such as human body fluids or in environmental samples.
Due to the progress achieved in increasing the sensitivity of assays by amplifying nucleic acid sequences, for instance by the Polymerase Chain Reaction (PCR), as disclosed in EP 0 201 184 and subsequent detection as disclosed in EP 0 200 362 molecular diagnostics has been established as a tool to determine nucleic acid containing parameters, like viruses and bacteria, for instance Hepatitis B virus and HIV. PCR based assays were developed using the so called heterogeneous format as disclosed in EP 0 420 260. In those assays, exemplified in Roche's AMPLICOR assays, nucleic acid sequences of a nucleic acid of a defined analyte, like Hepatitis B virus, are amplified and immobilized on so called capture probes contained in a tube. Due to the slow diffusion of nucleic acids to the capture probes, the immobilization required some time to come to completion. This disadvantage was avoided by the so called homogenous assays that did not need immobilized probes for the detection. An exemplary method is disclosed in EP 0 543 942.
Instruments for performing PCR were developed to conveniently perform the required thermal cycles needed to anneal the primers to the target nucleic acid, extend the primers using the target nucleic acid as a template, and separate the nucleic acid strands to provide single strands that can again bind the primers. A thermocycler useful to conduct thermocycles is disclosed in EP 0 236 069.
Due to the capacity of PCR to amplify nucleic acid sequences which are present in samples in only minute amounts and to amplify different sequences in one sample, assays were developed to amplify and detect several analytes or parameters independently in parallel. Particularly, if more then ten analytes are suspected to be contained and detected in one sample, those assays require the use of a corresponding number of probes, preferably immobilized to separate sites of a solid surface. The manufacture of chips containing a large number of different binding agents is disclosed in EP 0 476 014.
A device for holding chips and conducting analytical reactions in said device were proposed in EP 1 161 989. A first method for processing liquids in said device is disclosed in EP 1 226 863. In this method, a cartridge containing a chip is moved back and forth to mix the liquid contained in said cartridge. In EP 1 224 976 there is described a method for mixing a cartridge wherein the cartridge is swung back and forth to force the liquid to pass the surface of the chip. Those devices have very thin cavities in order to avoid transport of liquid from large distances to the surface of the chip. Thin cavities have the disadvantage that filling with liquid requires relatively complicated inlet and outlet channels and adapters to connect the inlet and outlet channel to a fluid system.
In EP 0 695 941 there is disclosed a flat device containing a chip having a flat cavity, inlet and outlet channels being arranged on the flat surface of the device. Again, the device is difficult to fill because the inlet and outlet channels need to be connected tightly to the instrument. EP 695941 describes a device in which a flat carrier is fixed to a body of a device using an adhesive which is applied to a gap around the flat carrier and the body of the device. This requires aligning the carrier and the device prior to applying the adhesive. Adhesives generally release organic solvents that may harm the reagents on the carrier. U.S. Pat. No. 6,043,080 describes a flat device containing a chip. This device again suffers from the same disadvantages.
Another device for holding chips is disclosed in EP 1 419 821. Because this device has a thicker cavity, diffusion of components of the liquid sample contained therein to the active surface takes too long for routine diagnostics. The reference describes the use of vortexing the liquid sample for mixing.
The devices presently known have the disadvantage that they are either relatively difficult to manufacture, do not provide reliable retaining of the sample and reagents or use adjuvants that may harm the reagents contained on the carrier.